Our daily farming activities are done with the confidence that our soils will function reliably and predictably and when things go wrong, such as failed drains or compaction, we have the knowledge and tools to address them.
With an unpredictable climate, our soils will need to be more resilient; three concerns which could increase in the face of a changing climate are:
- Increased variability in weather during land operations – It will be harder to avoid fieldwork during poor conditions which increase the risk of compaction.
- Drainage capacity – higher and more intense rainfall events will mean that water will need to be more effectively removed from the root zone to avoid yield penalties.
- Soil moisture-holding capacity – less reliable rainfall in the spring and summer will leave emerging crops at risk from drought.
The retention of crop residues and the application of organic fertilisers on an annual basis is the most important management tool to help increase the resilience of your soils from these risks. The annual process of biological decomposition is essential for both the retention and improvement of soil structure. Most of this organic material will end up feeding next year’s crop but the resulting increase in biological processes will improve soil structure which is the main characteristic that controls vulnerability to these risks.
There is no quick fix in terms of soil structural improvement and organic matter recycling is not the only factor, but it is one that every farmer can start improving on right away. The focus must be on maximising annual recycling of organic matter rather than “one-off” applications.
Key management options:
- Application of organic inputs such as composts and manures – these are often seen as ‘wastes’ but in the face of a changing climate, they are becoming a vital soil management tool.
- Recycling crop residues – harvesting of straw can be a profitable second crop but its value as a soil improver, when left in the field, must now be taken into account.
- Reduced tillage – This is not an easy option but when possible as much of the previous crops root system should be left intact underground.
Dr Bill Crooks, Soil & Water Consultant, SAC Consulting